I. Field of the Invention
This invention relates generally to interconnection of printed circuit boards and particularly to apparatus for interconnecting two personal computer style processor boards.
II. Description of Related Art
Industrial controls are known which are based upon personal computer hardware, realizing both cost savings of large scale production of such hardware and compatibility with a wide variety of compatible commercially available computer software. However, industrial controls, such as computer numerical controls place high demands on digital processing resources. In light of these demands, it is known to provide, for example, a processor dedicated to real-time control and another processor dedicated to supporting functions involving operator intervention, such as program generation and modification. Controls so arranged require means for interconnecting the processors, such as, for example, means for controlling access to a common bus for transfer of data between two processors. Such means for interconnection are absent from personal computer style "mother" boards, the printed circuit boards which comprise the central processor units of personal computers.
An aspect of the difficulty of providing interconnection of two personal computer style mother boards resides in the mechanical connection arrangement. The sole connecting means suitable for facilitating interconnection of personal computer style mother boards are sockets fitted to the mother boards for receiving edge connectors of "daughter" boards. This precludes the use of known arrangements for interconnection such as socketed backplanes and interconnecting cabling. The use of these sockets requires that the mother boards be arranged in facing parallel alignment with an interconnecting means providing edge connectors for engaging the sockets.
From European Patent Application 538 029A2 it is known to provide mating connector elements on two printed circuit boards to permit their interconnection in a space saving parallel arrangement. The printed circuit boards of this application have apertures to permit specially made connectors to be mounted so as to be recessed in the apertures to reduce the vertical distance between facing surfaces of the boards. This disclosure does not address any connecting arrangement for two commercial personal computer mother boards which are fitted with sockets for receiving edge connectors of daughter boards.
From French Patent Application 2 575 336 it is known to provide rigid supporting and connecting elements to join two printed circuit boards in a spaced parallel arrangement. The connectors of this application do not provide sliding contacts as do edge connectors and mating sockets. The disclosure of this application does not address a connecting arrangement for connecting two commercial personal computer mother boards to a third board.